Electric welding apparatus



Dec. 8, 1925. 1,564,892

,Gy H. PHELPS ELECTRIC WELDING APPARATUS Filed Jan. 2, 1925 Patented Dec. 8, 1925.

UNITED STATES PATE-NT OFFICE.

GEORGE H. PHELPS, WAREHOUSE P'OINT, CONNECTICUT, ASSIGNOR TO THOMAS E.

MURRAY, OF IBROOIKLYIII,A NEW YORK.

ELECTRIC WELDING APPARATUS.

Application led January 2, 1925. ASerial No. 82.

- To all whom, z't may concern:

Be it known that I, GEORGE H. PHELPS.,- a citizen of the United States, and resident of Warehouse Point, Connecticut, have invented certain new and useful Improvements in A,Electric Welding Apparatus, of whichv the following is a specification.

InQmy application 7 32,768, I have described a method of welding the edge of a iin of flange to the surface ofa tube to produce a heat conducting tube having certain advantages in specially constructed boilers.

My preserit application provides an apparatus to be used in carrying out the process of my previous application and analogous processes. s

The accompanying drawings illustrate an embodiment of the invention.

Fig. 1 is a cross-section;

jFig. 2 is a longitudinal section approximately central. v

Referring to the case illustrated, the tube 1 is of steel tubing such as is ordinarily used for boiler tubes, either seamless or made with a welded seam. A plate 2 is to be applied to form a fin on the tube. The

joint edge of the plate is preferably tapered.

The parts are pressed together, commencing with a light pressure and afterwards increasing it, while a welding current is passed across the joint. Preferably a current of extremely high ampere strength is applied for a very brief regulated period of time, as in the Murray Reissue Patent 15,466 of October 10, 1922. During the initial-light pressure an arc is formed raising the parts to a welding heat` in spite of the comparatively rapid loss of heat by conduction through the metal of the tube. The continued pressure is suicient to squeeze out all the burned or melted metal and inally to l ,form a good weld.

Where the tube is suciently thick, it will resist the pressure and practically maintain its shape 1n s ite -of being softened locally by the heat. v ut for thin tubes and where bending the'reor'- would be objectionable, it is advisable to use a backing or mandrel.,

Such a mandrel is shown in the present drawings composed of two principal parts 3 and 4 inthe shape of wedges. The part ,4 has a pair of .plates 5 fastenedY to its opposite faces to serve as guides for the part 3. Rods 6 and serve to pull the wedge 3 welding operation.

in onejdirection or the other, and rods 8 and 9 serve the same purpose for the wedge 4. The outer edges of the wedges arev shaped to lit the inner face of the tube, When the lwedges 'are shifted in the direction of the arrows, Fig. 2, they fill the tube and serve to support it against distortion in the When, the welding operation is completed, the wedges are pulled in opposite directions suiiiciently to contract the mandrel as a whole and to shift it to another point in the length of the tube. For tubes of considerable length, the welding will be done in successive operations along the length of the tube, the tube being moved stepby step longitudinally through the machine for this purpose.

One of the electrodes may be made in two parts l0 and 11 which fit the tube around nearly its entire periphery, with a narrow gap at one side for the iin and a similar gap at the opposite side. The opposite electrode may also be made in two parts 12 and 13 between which the iin is clamped for nearlyits entire width, this electrode having a projecting part 14 adapted to enter the gap between the parts of the opposite-electrode. A supportingbar 15 is arranged against the rear edge of the plate. The

lupper electrode is located on theV underside of a head 16 of the machine, and the lower electrode on the top of an opposite head 17.

they may be.. arranged horizontally; and the machine may be completed in detail in various known ways.

It is desirable to have the lowerI gap between the parts 10 and 11, narrow so that the current will not have to travel far to the point where the joint is to be made. It is also desirable that the parts 12 and 13 of the lower electrode shall extend close to the edge where the joint is to be made. It is thus advantageous to have thev lower electrode observ one; f The mandrel, it w is shaped so as to enter the 1lgapein the u per` therefrom that the invention is restricted to the particular embodiment illustrated., Various modifications thereof mayl be made by those skilled in the art Without departure from the invention as defined in the following claims.

'W hat claim is:

l. An apparatus of the character described comprising an electrode in tvvo parts adapted to embrace a tube, with a gap at a determined point and a second electrode adapted to be clamped to a projecting member With its edge inserted in said gap against the tube.

2. An apparatus ot the character described comprising an electrode in two parts adapted to embrace a tube, With a gap at a determined point and a second electrode adapted to be clamped to a projecting member with its edge inserted in said 'gap against the tube, in combination with a supporting device located Within the tube to hold the latter in shape against the pressure of Said projecting member during the Welding operation.

3 Am apparatus of the character descrlbed comprising an electrode in tvvo parts Langeac a determined point and a second electrode adapted to be clamped to a projecting member with its edge inserted in said gap against the tube, the latter electrode being adapted to enter in part into said gap.

ll. An apparatus of the character described comprising an electrode in two parts adapted to embrace a tube, With a gap at a determined point and a second electrode adapted to be clamped to a projecting member with its edge inserted in said gap against the tube, in combination -with a supporting device located Within the tube to hold the latter in shape against the pressure of said projecting member during the Welding operation, and supporting means for the outer edge or said projecting member during the Welding operation. i

5., An apparatus of the character described com'prising an electrode adapted to embrace a tube, with a gap at a determined point and a second electrode adapted to be clamped to a projecting member With its edge inserted in said gap against the tube.

6. An apparatus ot the character described comprising an electrode adapted to embrace a tube, With a gap at a determined point and a second electrode adapted to be clamped to a projecting member with its edge inserted in said gap against the tube, in combination with a supporting device located Within the tube to hold the latter in shape against the pressure ot said projecting member during the Welding operation.

ln Witness Whereotl have hereunto signed my name.

GEORGE H. PHELPS. 

